 | Too many data points, or "slices," make for an unusable pie chart. That is, there isn't a specific number of slices that your Excel pie chart should have. As a general rule, however, if youyou have more than eight data points, a pie chart is no longer the best choice for comparing data. Pie charts become unreadable when they contain a large number of tiny slices. A line chart or bar chart, on the other hand, may be a better choice when the chart contains many data points. These types of charts can display large numbers of data points without suffering a loss of clarity. |
Using a single series to make a pie chart
Pie charts display just a single series. For example, consider a pie chart that tracks the number of vacation packages that have been sold by the different offices of a chain of travel agencies. Figure 1 shows the data, displayed in columns A and B of the Excel worksheet, and the Chart Wizard, which is on its way to creating a pie chart.
Figure 1: Creating a pie chart.
Here's how to create a pie chart in Excel:
1. On a blank worksheet, enter two headers in two columns, across a row.
The example shows Office and Vacation Packages.
2. Underneath the first header, enter five category values.
These are not the actual measurements. The example uses the names of five Canadian cities where offices of the travel agency are located.
3. Enter numeric values under the second header.
A large discrepancy in values causes the smallest or smaller values to show up as very thin slices of the pie. That's not necessarily a bad thing, but don't be surprised if they're hard to find.
4. Select the data, including the headers.
5. Click the Chart Wizard button on the Standard toolbar or choose Insert --> Chart.
The Chart Wizard opens.
6. In Chart Wizard Step 1, select Pie as the chart type.
7. Select the second chart subtype (the second from the left in the top row of subtypes — pie with a 3-D visual effect).
8. Click Finish.
You now have a pie chart. The cities are listed in the legend, and the color of each identifies which pie slice belongs to which city.
Using labels to point out the exact values
Unlike some other chart types, you can't display a value axis on a pie chart. Therefore, the viewer gets no immediate clues to the actual values of the slices, although of course they realize that each slice represents a data point in the series.
 | Often, leaving out labels on a pie chart is fine. A pie chart is meant to show the contribution of each data point to the total. By using a complete circle as the total, you can easily grasp a data point's contribution by the size of its slice. That may be all you need — a general idea of the data point's contribution. |
However, sometimes you'll need to know the exact values. The way to do this is by adding data labels:
1. Click on the chart once to select it.
2. Choose Chart --> Chart Options.
The Chart Options dialog box appears.
3. Click the Data Labels tab to select it if it isn't already selected.
4. Check Value in the Label Contains box.
5. Click OK.
The data point values are now situated next to the slices.
Moving individual slices of a pie chart
After you've created a chart, you might want to "explode" the pie chart. Exploding the pie chart is moving any or all of the slices away from the center to draw attention to them or to improve the readability of the chart. Never fear: No TNT is necessary. Moving a slice of pie is a piece of cake (so to speak).
Clicking once on a particular slice selects the whole pie. Clicking a second time on the slice selects just the slice. After the slice is selected, you can move it by clicking once on it, holding down the mouse button, and dragging the slice out from the center.
| After you release the mouse button, the slice is in a new location. You can independently place each slice in a new location. Figure 2 shows a pie chart whose slices have been exploded away from the center. The pie slices can only be moved away from or back toward the center. You cannot arbitrarily move the slices around the plot area or chart area. |
Figure 2: Spreading the slices away from the center.
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